EXAMINATION AND PROOF OF GUNPOWDER.
Desired properties of gunpowder.
The great and ultimate object to be attained in the manufacture of Gunpowder is, not so much to produce that which ranges the highest, as one that shall be durable in its texture, not easily deteriorated by atmospheric influence or transport, and one with which equal charges shall produce equal effects. It should present uniformity in the appearance of its grains, which should be angular, crisp and sharp to the touch, not easily reduced to dust by pressure between the fingers, or dusty in handling; Specific gravity.its specific gravity should not be under 55lbs. to the cubic foot, (that of Waltham Abbey is generally 58lbs.) taking water at 1000ozs.; Strength.its strength is tested by firing three rounds from an 8 inch mortar, throwing a 68-pounder solid shot with a charge of 2oz. this should give a range of from 270 to 300 feet. The distance however, varies considerably, according to the state of the atmosphere, and the density of the powder: for, the greater the density, the less the range in small charges. Purity.Half an ounce flashed on a glass plate should leave little or no residuum; should white beads or globules appear, it is a sign of imperfect incorporation.
PROOF OF MERCHANT’S POWDER.
The following are the different proofs merchant’s powder is subjected to:—
Lots of 100 barrels are sent in, marked with the number of the lot and the maker’s name on the head of each barrel. 25 per cent. of these are unheaded in the examining house; the Proof Officer then—
If dusty.
First, takes a bowl out of each barrel, and holding it about three feet above, pours it out quickly; should there be a good deal of dust, it is satisfactorily shown by this means.